This invention relates generally to slot machines, also known as coin operated gaming machines, and more specifically to a category of slot machines that does not require winning lines to determine a winning combination of symbols.
Slot machines are well known, and have been around for many years. Various mechanical reel type slot machines are known in the art, and require one, or a plurality of winning lines to make a win determination after a spin. Similarly, a reel type video slot machine includes a plurality of symbols that are mapped on the periphery of a plurality of simulated rotating reels that form a playfield of m columns, and n rows. The reels are randomly stopped, and a win decision is made based on the combination of symbols occurring at one, or a plurality of winning lines (also known as pay lines). Further, the number of reels employed varies from one reel per column to an individual reel for each playing position.
Another type of slot machines eliminates pay lines, and defines a winning combination based on the multiple occurrence of a symbol at any location at consecutive reels, rather than at a particular pay line that spans the reels (see U.S. Pat. No. 6,093,102).
For a five reel video slot machine that does not employ pay lines, and which uses 3 playing positions per reel, the player is required to bet a wager for each reel selected. For the first wager, the playfield normally consists of a horizontal line that spans the middle positions of all five rotating reels, in addition to the two visible playing positions of the first reel. Upon depositing a second wager, the playfield is expanded to include the remaining two visible playing positions for the second reel. A third wager expands the play field to include the two remaining visible playing positions of the third reel, etc. For the five reel machine, when a player deposits five wagers, the entire playfield, which includes 15 playing positions, is activated. Normally, the activation of the playfield is done sequentially from left to right, and is based on the amount of wager deposited. The player has also the option to place a maximum bet, and in such case the entire playfield is activated with multiple wagers per reel. A winning outcome includes the occurrence of three of a kind, four of a kind, five of a kind, etc. In a winning combination a symbol must be present at consecutive reels starting at the first reel at the left of the playfield.
The above described slot machine has two main limitations. It is still constrained by the configuration of fixed rotating reels for the definition of an active playfield. Further, a winning combination of symbols must be contiguous. The slot machine described in this invention is independent of rotating reels configurations for the definition of a playfield, and enables a player to partially define an active playfield as a subset of any playfield that consists of a plurality of playing positions. Further, because each playing position is independent of the remaining positions, i.e. is not constrained by a reel configuration, a winning combination of symbols does not have to be contiguous.